Digital processing and presentation of information is now in wide spread use in the consumer electronics and personal computing industries. Video, audio and text are now digitally manipulated and presented in a variety of applications.
In particular, digital display terminals are fast becoming commonplace—rapidly replacing older analog devices such as cathode ray tube displays. Digital video transmission may take place between two integrated circuits in a given display device or between two external devices. Device-to-device digital video exchange may be observed between computers and monitors, set-top boxes and television displays, projectors and display terminals, and the like.
To facilitate flexible transmission of digital video data between a transmitting device and a receiver, various standards defining suitable communications are evolving. The current trends use a serial link, to carry one or more digital data streams.
The DisplayPort standard, for example, provides a high bandwidth (currently 2.7 Gbps per stream), multi-stream forward transmission channel across a data link, with a bit error rate (BER) of no more than 10−9 per stream. Each serial stream is referred to as a lane. DisplayPort further provides for a bi-directional auxiliary channel and an interrupt request line from the receiver to the transmitting device, to facilitate link training and the exchange of control data. Pixels in a digital video frame may be sent in parallel using symbols across all lanes. DisplayPort is more particularly described in The DisplayPort Standard v. 1.0, as published by the Video Electronics Standards Association (VESA), the contents of which are hereby incorporated by reference.
Conveniently, the format of the frames is flexible, to accommodate multiple different video formats. Each video format may have a different pixel resolution (number of pixels per line, number of lines per frame); color depth per pixel; color format; and the like.
At relatively high data rates, achieving the required BER may present multiple design challenges. At the same time, interoperability between devices requires that possibly interconnected devices provide video signals in a recognizable and standards compliant fashion for the multiple video formats.
Accordingly, each device design purporting to be interoperable and compliant with the standard may undergo rigorous standards compliance testing. In such testing, a test device is usually placed in different modes, each corresponding to a supported video format. In each mode typically, compliance of the received or provided video signal to the standard may be verified. As well, the establishment of the link, and the exchange of auxiliary data may be verified. Typically, all this is done manually, and is quite time consuming. It is particularly time consuming as the number of supported video modes, and link types and modes of operation increases.
Therefore, there remains a need to allow for more automated device testing.